The brother and nephew of Lori Vallow, who with her husband Chad Daybell is charged murdering her two children, said the union between Vallow, obsessed with death and the afterlife, and Daybell, a doomsday evangelist, was the "perfect storm."
"They were ready to be taken," said Vallow's brother, Adam Cox on "The Followers: Madness of Two" podcast, which is exploring the case.
"I don't think there was one kind of leading the other," said Adam's son, Zac Cox. "Lori was, before she had even met Chad Daybell, she was listening to podcasts by Julie Roe," a self-proclaimed clairvoyant who says she has had visions about the end times.
"Chad was doing his thing, and that's why it's kind of the perfect storm," Zac said.
Daybell is a self-published author who has written more than two dozen books about near-death and doomsday events.
"Lori talked about death a lot actually, talked about the next life, how great the next life is and how it's going to be perfect, and how her kids won't have to suffer in the next life," Adam said. "If she says, 'I'm not going to tell you where the kids are,' that means the kids aren't alive. And I knew right then and there that the kids are dead."
Tylee was last seen on Sept. 8, 2019. Police were able to find a photo from that day of Tylee on a trip with Vallow, Vallow's brother, Alex Cox, and Joshua (JJ) to Yellowstone National Park, according to authorities.
JJ, who was adopted and had special needs, was last seen alive on Sept. 23, 2019 at Kennedy Elementary School in Rexburg.
But Vallow and Daybell had never reported the children missing and did not cooperate with investigators before they fled their home in Idaho, police there said.
The couple was found in Hawaii in January 2020, at which point authorities gave Vallow until the end of the month to "physically produce her children." She did not, and was charged with two counts of desertion and nonsupport of dependent children.
The remains of Tylee and JJ were found on Daybell's Idaho property in June of 2020.
"That day I just was sick," Zac said. "I'm going one day at a time, and it's been really really hard on me. It's hard on me to think about what happened." Zac lived with Vallow, her fourth husband, Charles, and the kids for more than a year starting in late 2017 and thought of Tylee and JJ as siblings.
Charles Vallow died in 2019. He was shot to death by Vallow's brother, Alex Cox, during a confrontation in Chandler, Arizona. Alex Cox claimed self-defense. The Maricopa County Medical Examiner in Arizona ruled the death a homicide.
Vallow and Cox were not charged at the time, but Vallow has since been charged in connection with Charles Vallow's death.
Alex Cox died in December of last year of an apparent blood clot in his lung. He has been named by prosecutors as a co-conspirator in the murders of JJ, Tylee and Daybell's previous wife, Tammy Daybell.
Adam and Zac said Alex Cox had also been indoctrinated with the same end-of-times beliefs as Vallow and Daybell.
"There's a lot of things I wish I would have done different in 2019 when things were kinda going downhill and before Charles was killed," Zac said. "I just wish that I would have said something sooner, and if I had done that maybe they would have listened earlier and things would be different if we would have done something to help Lori or stop her."
In May, Vallow was declared mentally unfit to stand trial for separate concealment of evidence charges she faces and committed to a mental health facility in June. Court documents from last week show she has been ordered to remain committed for at least 180 days because she is mentally unfit to defend herself against the charges alleging she murdered her children.
Daybell, who has also been indicted on a charge of first-degree murder and insurance fraud in the death of his once-wife Tammy Daybell, is due in court next week. Prosecutors have said they will seek the death penalty in his case.
Attorneys for Daybell and Vallow did not immediately respond to NBC News' requests for comment Wednesday.
Adam said Vallow, in recent letters to their parents, has said she refuses to talk with authorities about the case.
"She's still in the same state of mind ... as far as believing that she's chosen, her and Chad are chosen to be whatever for the second coming," Adam said. "With scriptures, they got all twisted up the way that Chad explained things the way that she interpreted things."
Adam said he and Vallow were raised Mormon, but the family was not strict. He describes an idyllic childhood with his sister and three other siblings.
Lori "had a lot of things going for her - like a lot. And she was always happy and loving and smiling and, you know, was just like a normal sister," Adam said.
He said he believes his sister suffers from mental illness and was drawn to cultish beliefs after four failed marriages and not "having her life not turn out the way she thought it would or wanted it to."
Adam said when Vallow began talking to him about her new convictions, he confronted her about it, and she cut him off.
"She's torn our whole family apart. Our family is not even close to being close because of her decisions," Adam said. "The ripple effect is unbelievable about what it's done to our family."
But still, he can't wish the worst for his sister.
"I don't know what mental illness does to your brain," he said.
Either way, "there's no justice" for JJ and Tylee, Adam said."There is no justice for them. That's not for me. That's for the Lord to decide."
Zac disagrees with his father.
"It's life in prison or death penalty," he said. " It's not for the Lord."